Bimodal White Particles for Display Aggregation Control
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Solution Overview
Problem
Conventional display media using colored particles face issues with particle aggregation, leading to display defects and irregularities in whiteness, particularly when showing single or multiple colors, due to the lack of effective size and mobility-based particle distribution.
Innovation Solution
The use of white particles with distinct size and mobility characteristics, where larger particles move in response to an electric field to agitate the dispersion medium and prevent aggregation, while smaller particles remain stationary to maintain whiteness and stability, with a specific size ratio and composition to optimize their roles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If only colored particles are used in the display medium, then the display can show colors, but particle aggregation occurs leading to display defects and irregularities in whiteness
Solution Approach 1:
The particle system is segmented into three distinct types based on size and function: colored particles (for color display), large white particles (for agitation and aggregation prevention), and small white particles (for whiteness maintenance). This segmentation allows each particle type to perform its specific function without interfering with others, resolving the aggregation problem while maintaining color display capability.
Solution Approach 2:
The invention changes the particle size parameter by introducing a bimodal white particle distribution with specific volume average particle sizes (large: 1-30 μm, small: 0.1-3 μm) and controls the numerical ratio between different particle types (L/S ratio: 1/(5.1×10^7) to 1/(2.8×10^4)). These parameter changes optimize the balance between color display, whiteness, and aggregation prevention.
2Reliability
If white particles are added to prevent aggregation, then display uniformity improves, but the complexity of particle composition increases
Solution Approach 1:
The large white particles serve multiple functions simultaneously: they act as agitation particles to prevent aggregation of colored particles, serve as scattering particles to maintain whiteness, and function as spacers to maintain particle distribution. This multi-functionality reduces the need for separate particle types and simplifies the overall system despite the presence of multiple particle sizes.
3Object-generated harmful factors
If large white particles are used to agitate the dispersion medium, then particle aggregation is suppressed, but the stability of the dispersion medium may be affected
Solution Approach 1:
The large white particles perform periodic agitation movements in response to applied voltage, creating cyclic disturbance patterns that continuously prevent particle aggregation. This periodic action maintains particle dispersion stability over time by repeatedly disrupting potential aggregation zones without causing permanent destabilization of the dispersion medium.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses particle aggregation, ensuring a high degree of whiteness and stability in the display medium, reducing display irregularities and improving the clarity of white and colored displays.
Implementation Method 1
first white particles that move in response to an electric field
Implementation Method 2
emulsifying the mixture by applying ultrasonic waves
Data Source
AI summary
White particles for display including first white particles that move in response to an electric field and second white particles that do not move in response to an electric field, the second white particles having a volume average particle size that is less than that of the first white particles, and a ratio of the numerical amount of the first white particles/the second white particles (L/S) satisfying the following relationship: 1/(5.1×107)≦L/S≦1/(2.8×104).